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TPD2S300: Dead Battery mode - USP

Part Number: TPD2S300

In the data sheet it states :-

If desiring to power the CC/PD controller during dead battery mode and if the CC/PD Controller is configured as 
a DRP, it is critical that the TPD2S300 be powered before or at the same time that the CC/PD controller is
powered. It is also critical that when unpowered, the CC/PD controller also expose its dead battery resistors.
When the TPD2S300 gets powered, it exposes the CC pins of the CC/PD controller within 200 μs. Once the
TPD2S300 turns on, the RD pull-down resistors of the CC/PD controller must be present immediately, in order to
guarantee the power adaptor connected to power the dead battery device keeps its VBUS turned on. If the power
adaptor sees the CC voltage go high to the SRC.Open region, it can disconnect VBUS. This removes power from
the device with its battery still not sufficiently charged, which consequently removes power from the CC/PD
controller and the TPD2S300. Then the RD resistors of the TPD2S300 are exposed again and connect the power
adaptor's VBUS to start the cycle over. This creates an infinite loop, never or very slowly charging the mobile
device.

Is there any such requirements when the CC Controller is configured as a UFP ???

  • The loop that you are describing sounds correct to the PD standard to me. It is supposed to cycle the way that you describe until connection is mode.

    The TPD2S300 utilizes the VPWR pin to determine if it should exit it's dead battery mode and pass control of the CC bus to the PD controller. If you need the bus to stay inactive, then you will need to prevent VPWR from being applied to the TPD2S300 or ensure that your PD controller holds the CC bus in legacy mode until your device is fully charged.
  • In reply to Chuck Branch:

    Sorry Maybe I wasn't clear enough - the data sheet I mentioned was that of the TPD2S300, and it appears to be describing a device that is configured as a DRP. However my device is configured as a UFP thus my question was - how does this paragraph relate to my configuration if at all ? i.e. is there any such recommendations for the TDP2S300 device when it is used in conjunction with a CC controller configured as a UFP ???
  • In reply to Shmuel Davis:

    The TPD2S300 is not designed to recognize the difference between a DRP and a UFP. It will present the proper resistances when not powered and then pass control to the PD device once power is applied. It has no protocol awareness.
  • In reply to Chuck Branch:

    Dear Chuck,

    Thanks for this reply.

    I understand that the TPD2S300 does not recognize the difference between if it working with a DPR or a UFP, i.e. that it has "no protocol awareness". However the part of the data sheet of the TPD2S300 that I originally quoted appears to indicate that there are specific considerations and requirements that are definitely needed when the TPD2S300 is used in conjunction with the controller that is configured as a DPR. My question was since I am using the TPD2S300 with a controller that is to be configured as a UFP is there any similar requirements needed to be considered ?

    Shmuel
  • In reply to Shmuel Davis:

    Shmuel,

    For a UFP, the TPD2S300 will have the same requirements as the DRP case. The dead battery resistance needs to be presented by the PD controller for the dead battery case. This way when the connection between the DFP and UFP is made, there is no interference on the line.


    Regards,
    Chuck
  • In reply to Chuck Branch:

    Dear Chuck,

    Thanks for that clarification. Maybe you want to suggest to TI that the data sheet be updated with this clarification.

    I am using the TPD2S300 in conjunction with TI TUSB320LA and they are powered from the same +3.3V supply so I assume that the above mention configuration specification is fulfilled !

    However I am also using a 2nd TPD2S300 in conjunction with a TI HD3SS3220 whose VCC33 is powered by the same +3.3V supply as the TPD2S300. However the VDD5 of the HD3SS3220 is connected to the +5V VBUS which is powered before the the +3.3V supply of the TPD2S300 ! Can I assume that this configuration will still meet these specific Powerup requirements ?

    Best regards

    Shmuel
  • In reply to Shmuel Davis:

    Shmuel,

    I do not see any issue with you connection as described. The most important sequencing issue is the PD controller and the PD protection on the CC lines and that connection is powered by the same connection.

    The high speed USB lines are effectively independent of the PD control in the interface, so there is no issue in your configuration.

    Regards,
    Chuck

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